Diffraction Profile Analysis Research Articles

Identification of a Ternary Nitride Ti10Cu3N4 with a Unique Structure Type.

This study presents the synthesis and detailed structural analysis of the ternary nitride Ti10Cu3N4. Initially identified as Ti3CuN within the Ti-Cu-N ternary phase diagram, its crystal structure remained unresolved and was characterized solely as belonging to the tetragonal crystal system. Through a comprehensive structural analysis, this study proposes a revised stoichiometry as Ti10Cu3N4; its crystal structure represents a previously unreported structure type within the P4 2 /mnm space group. Its atomic arrangement was elucidated through a combination of X-ray powder diffraction profile analysis and density functional theory calculations, corroborated by neutron diffraction studies. Furthermore, the hydrogen storage properties of Ti10Cu3N4 were characterized, demonstrating a hydrogen absorption capacity of approximately 0.6 wt % with desorption occurring in the temperature range of 200-550 °C.

X-ray diffraction profile analysis of green synthesized ZnO and TiO2 nanoparticles

ZnO and TiO2 nanoparticles were prepared through a plant-extract mediated hydrothermal synthesis. X-ray diffraction (XRD) study confirmed the crystalline nature and the phase characteristic of the obtained nanoparticles. X-ray diffraction profile analysis models such as Williamson–Hall analysis, size-strain plot and Rietveld analysis were further used in evaluating the microstructural parameters of the obtained materials. The calculated particle size for all the models was in great agreement, with values in the range of 55.46–87.6 nm recorded for ZnO, while for TiO2, the crystallite size was in the range of 33.82–41.9 nm. The calculated crystal microstrain varied based on the model, while the stress in the ZnO and TiO2 nanoparticles was evaluated at 3.8 and 13.7 MPa, respectively. Furthermore, TiO2 nanoparticles had a higher energy density of 8.96 × 10–8 KJ m−3 compared to 7.12 × 10–8 KJ m−3 obtained for ZnO.

On the resolution of the three-axis neutron diffractometer setting optimized for some powder diffractometry studies

Presented three-axis neutron diffractometer performance documents the feasibility of using it in special cases high-resolution powder diffraction studies, namely, for elastic and plastic deformation studies of bulk polycrystalline samples when the whole powder diffraction spectrum is not required. Contrary to the conventional double-axis setting the suggested alternative consists of an unconventional three axis set-up employing a bent perfect crystal (BPC) monochromator and analyzer with a polycrystalline sample in between. The analysis of the profile of the beam diffracted by a sample is carried out by rocking the BPC-analyzer and the neutron signal is registered by a point detector. Though the diffractometer alternative is, for measurements, much more time consuming, its resolution is, however, substantially higher and permits also plastic deformation studies on the basis of analysis of the sample diffraction profiles. The so-called analyzer rocking curve then provides a sample diffraction profile and could reflect the lattice or structural changes. Moreover, much larger widths (up to 10 mm) of the irradiated gauge volumes can be investigated when just slightly affecting the resolution of the experimental setting.

Hydrodeoxygenation of Anisole via Cu supported on Zeolite: HZSM-5, MOR, and Indonesian Activated Natural Zeolite

The conversion of biomass waste into an alternative energy source requires effective and efficient hydrodeoxygenation (HDO) catalysts. This research aimed to synthesize a bifunctional zeolite-based catalyst for anisole conversion into BTX. The noble metal Cu was impregnated on HZSM-5, mordenite, and Indonesian activated natural zeolite (ANZ) to form HDO catalysts. X-ray fluorescence (XRF), X-ray diffraction (XRD), surface area and pore profile analysis, Fourier transform infrared analysis, ammonia-temperature programmed desorption (NH3-TPD), pyridine gravimetry, morphology, and scanning electron microscopy-energy dispersion elemental mapping (SEM-EDX) were used to determine the catalyst's properties. The HDO reaction test used anisole as a model compound in a semi-flow reactor with hydrogen gas at 350 and 500 °C for 1 h. Copper nanocrystals were found on the surface of the zeolites in several metal phase types, including Cu, Cu2O, CuO, and Cu(OH)2. Due to the copper bonds inside the zeolite pores, the internal pore surface area decreased. The acidity also decreased since it is strongly related to the surface area. At 350 °C, Cu was found to be less active. However, at 500 °C, copper activity increased, leading to an increase in anisole conversion and BTX selectivity. The catalyst with the highest anisole conversion and BTX selectivity was Cu/HZSM-5 (i.e., 53.28 and 13.06% v, respectively).

Phase transitions and slow spin dynamics of slightly inverted A-site spinel CoAl2−x Ga x O4

We report the properties of an A-site spinel magnet, CoAl2−x Ga x O4, and analyze its anomalous, low-temperature magnetic behavior, which is derived from inherent, magnetically frustrated interactions. Rietveld analysis of the x-ray diffraction profile for CoAl2−x Ga x O4 revealed that the metallic ions were randomly distributed in the tetrahedral (A-) and octahedral (B-) sites in the cubic spinel structure. The inversion parameter η could be controlled by varying the gallium (Ga) composition in the range 0.055 ⩽ η ⩽ 0.664. The composition-induced Néel-to-spin-glass (NSG) transition occurred between 0.05 ⩽ η ⩽ 0.08 and was verified by measurements of DC-AC susceptibilities χ and thermoremanent magnetization (TRM) below the Néel transition temperature T N. The relaxation rate and derivative with respect to temperature of TRM increased at both T N and the spin glass (SG) transition temperature T SG. The TRM decayed rapidly above and below these transitions. TRM was highly sensitive to macroscopic magnetic transitions that occurred in both the Néel and SG phases of CoAl2−x Ga x O4. In the vicinity of the NSG boundary, there was a maximum of the TRM relaxation rate at T max < T N. With increasing inversion η(x), the anomaly at T max merged with that of the Néel transition at a tricritical point (η tc, T tc) = (0.08, 4.0 K), where the paramagnetic, Néel, and SG states met. We successfully extracted the relaxation time τ and other characteristic parameters from the TRM isothermal temporal evolution based on the Weron function derived for a purely stochastic process. To distinguish the magnetic states, we compared our results with previously studied inversion-free A-site spinel, CoRh2O4, and CoGa2O4 cluster glass. We generated an inversion-temperature phase diagram based on the comprehensive measurements of DC and AC susceptibilities, TRM, and specific heat in the range 0.055 ⩽ η ⩽ 0.664 for CoAl2−x Ga x O4. Based on this phase diagram, we speculate that a NSG quantum critical phase transition occurred at η = 0.050(6). Our findings are consistent with suppression of the long-range order antiferromagnetic state in CoAl2O4 revealed through neutron diffraction studies, even at T << T N.

Environmentally friendly synthesis of lead halide perovskites using aqueous solutions

In this study, we demonstrate a successful method to synthesize lead halide perovskites (CH3NH3PbX3, X = Br, and I) by immersing lead halides (PbX2) powder in saturated aqueous solutions of methyl ammonium halides (CH3NH3X). Our analysis of reflection spectra and X-ray diffraction profiles confirmed the formation of the lead halide perovskite structures with this exposure process. This approach provides a promising pathway for environmentally friendly perovskite solar cells, eliminating the need for toxic polar organic solvents (for example, DMF, DMSO and so on) commonly employed in conventional perovskite solar cell fabrication.

γ′-size effect on the deformation microstructure and texture in a Ni-based superalloy using in-situ neutron diffraction

The γ′-size effect on the evolution of microstructure and grain rotation during tensile deformation in a polycrystalline Ni-based superalloy was investigated by in-situ neutron diffraction technique. Diffraction profile analysis was employed to evaluate the dislocation density and deformed subgrain size distribution, revealing that alloys with fine and coarse γ′ possess dislocation shearing and Orowan dislocation bypassing, respectively. The high strain hardening in the coarse γ′ specimen is attributed to the more pronounced accelerated accumulation of dislocations compared to the fine γ′ specimen. Moreover, the specimen with coarse γ′ precipitate exhibits a lower orientation rotation rate, resulting in weaker <111> and <100> fiber texture components upon tensile straining. The use of neutron diffraction combined with electron microscopy provided multiscale insights into the deformation microstructure and changes in the lattice orientation.

Quantitatively evaluating respective contribution of austenite and deformation-induced martensite to flow stress, plastic strain, and strain hardening rate in tensile deformed TRIP steel

Transformation-induced plasticity (TRIP)-assisted steels exhibit an excellent combination of strength and ductility due to enhanced strain hardening rate associated with deformation-induced martensitic transformation (DIMT). Quantitative evaluation on the role of DIMT in strain hardening behavior of TRIP-assisted steels and alloys can provide guidance for designing advanced materials with strength and ductility synergy, which is, however, difficult since the phase composition keeps changing and both stress and plastic strain are dynamically partitioned among constituent phases during deformation. In the present study, tensile deformation with in situ neutron diffraction measurement was performed on an Fe-24Ni-0.3C (wt.%) TRIP-assisted austenitic steel. The analysis method based on stress partitioning and phase fractions measured by neutron diffraction was proposed, by which the tensile flow stress and the strain hardening rate of the specimen were resolved into factors associated with each phase, i.e., the austenite matrix, deformation-induced martensite, and the transformation rate of DIMT after differentiation, and then the role of each factor in the global strain hardening behavior was discussed. In addition, the plastic strain partitioning between austenite and martensite was indirectly estimated using the dislocation density measured by diffraction profile analysis, which constructed the full picture of stress and strain partitioning between austenite and martensite in the material. The results suggested that both the transformation rate and the phase stress borne by the deformation-induced martensite played important roles in the global tensile properties of the material. The proposed decomposition analysis method could be widely applied to investigating mechanical behavior of multi-phase alloys exhibiting the TRIP phenomenon.

Crystal Structure of Poly(7-heptalactone)

The crystal structure of poly(7-heptalactone) (PHL) is presented. PHL has been synthesized by a combination of ring-opening polymerization of η-heptalactone and reversible addition–fragmentation chain transfer polymerization using diphenyl phosphate as catalyst. The noncommercial available η-heptalactone monomer has been prepared by oxidation of cycloheptanone. The crystal structure of PHL has been determined by analysis of the X-ray powder diffraction profiles and of the electron diffraction patterns of single crystals and calculations of lattice energy. The structure has been refined with the Rietveld full-profile refinement. Chains in trans planar conformation are packed in an orthorhombic unit cell with axes a = 7.37 Å, b = 5.05 Å, and c = 10.07 Å according to the space group symmetry P21.

Investigation on electrical transport and dielectric relaxation mechanism in TbCrO3 perovskite orthochromite

Herein, the TbCrO3 (TCO) chromite was synthesized by the sol-gel auto-combustion route and sintered at 900 °C. The Rietveld analysis of the room temperature powder X-ray diffraction profile confirmed the single-phase formation of the material crystallized in the orthorhombic phase of the perovskite structure with Pbnm space group symmetry. The surface morphology, the elemental composition, and the chemical states of the compound were investigated by field emission scanning electron microscopy, energy dispersive X-ray analysis, and X-ray photoelectron spectroscopy, respectively. The electronic density of states, band structure, and electron density were analyzed by Density Functional Theory. The electrical transport and dielectric relaxation mechanism were investigated using complex impedance spectroscopy over the experimental frequency and temperature ranging from 40-1.2x106Hz and 138−273 K, respectively. Two semicircular arcs in the impedance complex plane plots were modeled to an equivalent circuit configured by RG∥QG+RGB∥QGB which were attributed to the contributions of the highly resistive grain boundaries and relatively conducting grains in the material. The electrical conductivity as a function of frequency followed Jonscher’s universal power law behavior and an increasing nature of the temperature-dependent frequency exponent suggested small polaron hopping as the electrical conduction mechanism of the material. The least capacitive response of the TCO system was investigated by the complex electrical modulus formalism and the frequency-dependent imaginary modulus spectra were modeled by the Kohlrausch–Williams–Watts function, which resolved the thermally activated peaks of bulk and interface effects to the dielectric relaxation mechanism. The dielectric constant exhibited Maxwell-Wagner interfacial polarization effects and the dielectric loss factor showed frequency dispersion at all temperatures.

Vacancies Introduced during the Crystallization Process of the Glass-Ceramics Superionic Conductor, Na3PS4, Investigated by Neutron Total Scattering and Reverse Monte Carlo Method

Sodium solid electrolytes are expected to be safer and more durable than lithium solid electrolytes, which affect the properties of all-solid-state lithium-ion batteries nearing commercialization. The heat treatment of Na3PS4 glass ceramics, a strong candidate for sodium solid electrolytes, results in ionic conductivity exceeding 10–4 S cm–1 at ambient temperature, depending on the heat-treatment conditions. First-principles calculations have suggested that vacancies at Na sites promote ionic conduction; however, the existence of vacancies has not been confirmed through a conventional average structure analysis of X-ray and neutron diffraction profiles or pair distribution functions. In this study, local structure analysis of Na3PS4 glass ceramics using reverse Monte Carlo modeling was performed on the pair distribution function obtained from neutron total scattering measurements during and after heat treatment to identify the vacancy locations that differ from the Na occupation sites. The vacancies in Na3PS4 glass ceramics after heat treatment revealed a more disordered atomic arrangement than Na, suggesting that the vacancies connecting Na occupation sites are most likely responsible for the promotion of Na ion conduction. The control of vacancies in solid electrolytes is essential for the design of practical all-solid-state sodium batteries.

On the possibility of fabricating fully austenitic sub-micron grained AISI 304 stainless steel via equal channel angular pressing

The paper concerns possibility of increasing yield and ultimate stress of austenitic stainless steels by equal channel angular pressing (ECAP). To this end, an AISI 304 stainless steel subjected to eight passes of ECAP in a 105◦ die at 350◦ C. The evolution of microstructure as a function of induced plastic strain (number of passes) was studied in different length scales using light and scanning transmission electron microscope (STEM). An insight into fine details of dislocation structure was possible via X-ray diffraction profile analysis. Changes in the structure of processed samples were correlated with their mechanical properties as determined by tension tests and microhardness measurements. Light microscopy revealed a shear banded microstructure. STEM observations demonstrated co-existence of three types of grain structure: (a) short elongated grains/subgrains of 71 nm average width formed within the shear band regions, (b) a mixture of coarse (200–350 nm in size) and nanocrystalline (15– 70 nm) equiaxed grains developed outside the shear bands, and (c) nano-twin lamellae of 3–20 nm width inside nanocrystalline grains. XRD peak profile analysis using modified Warren–Averbach approach yielded dislocation density as ρ = 4.71 × 1015 m−2 after eight passes. ECAP-induced changes in the microstructure led to a remarkable increase in yield strength of the alloy (YS=1498 MPa, about 3.5 times the initial amount). At the same time, a moderate ductility of εf = 12% was maintained, primarily due to a large post-necking elongation. This behavior was explained by an increase in the strain rate sensitivity of ECAP-ed material in combination with the contribution from transformation induced plasticity, TRIP effect, caused by formation of ∼ 22 vol% martensite during room temperature straining.

Evolution of austenite lattice parameter during isothermal transformation in a 0.4 C low alloyed steel

The evolution of internal stress during displacive transformation is a topic of continuous debate. Neutron diffraction was used to study the isothermal bainite transformation in a 0.4 C low alloyed steel from 773 to 623 K to provide a clearer basis for discussion regarding the change in the austenite lattice parameter. According to diffraction profile analysis, fresh bainite possesses a body-centered tetragonal structure, and its c/a ratio decreases rapidly over time. The austenite lattice parameter increases or decreases depending on whether the transformation temperature is above or below the nose of the Time-Temperature-Transformation (TTT) curve. This isothermal transformation behavior can be divided into two categories: above and below the nose of TTT curve, which correspond to the upper and lower bainites, respectively. The internal stresses caused by the transformation strains are relaxed by dislocation motion and vacancy formation. The yielded dislocations and vacancies not only affect the broadening of both austenite and bainitic ferrite diffraction peaks but also the lattice parameter. The first-principles calculations demonstrate that the austenite lattice parameter decreases as the vacancy density increases, which may account for the experimental observation in lower bainite.

X-ray diffraction profile analysis of martensitic Ti6Al4V (ELI) parts produced by laser powder bed fusion

The quantification of the density of defects in materials through non-destructive methods is of great interest to scientists and engineers. X-ray diffraction (XRD) peak profile analysis is a valuable method that is often used to reveal important microstructural information, such as defects present in crystalline materials as well as crystallite size. In this study, the broadening of XRD peaks of martensitic Ti6Al4V (ELI) produced by laser powder bed fusion (LPBF) was studied following modified Williamson-Hall (MWH) and Warren-Averbach (WA) analytical methods. The level of defects in martensitic LPBF Ti6Al4V (ELI) was found to drastically reduce by at least 73% after exposing the material to stress-relieving heat treatment.

X-ray diffraction (XRD) profile analysis and optical properties of Klockmannite copper selenide nanoparticles synthesized via microwave assisted technique

In this study, copper selenide (CuSe) nanoparticles (NPs) were prepared using the microwave irradiation technique. The effect of the irradiation time on the structural properties of CuSe NPs was investigated. The XRD results confirms the formation of the hexagonal (Klockmannite) structure of CuSe NPs. Different X-ray diffraction profile analysis techniques comprising strain-size plot (SSP), Scherer’s method (S-M), Monshi-Scherer’s method (MSM), Halder-Wagner (H–W) technique, and Williamson-Hall technique (WHM) were employed to examine the effect of irradiation time on the particle size as well as intrinsic strain of CuSe NPs using XRD peak broadening analysis. Uniform deformation model, uniform stress deformation model, as well as uniform energy density deformation model of Williamson-Hall technique were used to calculate the average crystallites size of CuSe NPs. Essential physical variables involving stress and energy density were also computed. Also, field emission scanning electron microscope (FESEM) in addition to atomic force microscopy (AFM) were further used to determine the mean particle size of CuSe NPs depending on varying irradiation time. The obtained results were found to be in agreement and comparable with the results of XRD profile analysis methods. Raman spectroscopy revealed three vibrational bands which are ascribed to the CuSe vibrational modes. Furthermore, the optical characteristics of the synthesized CuSe NPs were also investigated. The result obtained revealed a decrease in the optical bandgap from 2.43 to 2.71 eV with increase in irradiation time. Photoluminescence study revealed two peaks at 530, and 610 nm respectively. Therefore, it can de deduced that inclusion of intrinsic strain play an important role on the estimation of CuSe NPs size and microstrain of CuSe NPs synthezed vi microwave assisted synthesis technique.

Advanced analysis of the X-ray diffraction profile of carbon

Advanced analysis of the X-ray diffraction profile of carbon

Advanced analysis of X-ray diffraction profile of carbon

Advanced analysis of X-ray diffraction profile of carbon

Synthesis and characterization of new multiferroic (BiBa)(FeTi2)O8

The present communication reports the study of various properties (i.e., structural, electrical, dielectric, ferroelectric, and magnetic) of new multiferroic: (BiBa)(FeTi2)O8 synthesized by a mixed oxide reaction route. The analysis of the X-ray diffraction profile at room temperature ensures its phase formation in the orthorhombic crystal structure. The micrographic study divulges irregular shape grains (mostly rectangular) with an average grain size of 3.5 μm. The compositional study displays the desired stoichiometry. The study of electrical (impedance, modulus, and conductivity) and dielectric properties (dielectric constant and tangent loss) of the sample at different temperatures (RT – 773 K) and electric field frequency (1 kHz-1MHz) provides many new experimental data, and insight mechanisms. The temperature dependence of the dielectric constant exhibits a dielectric anomaly around 523 K that may be due to the combined effect of oxygen vacancy mediated redox reaction (Fe3+→Fe2+ and Ti4+→Ti3+) and Maxwell-Wagner polarization. The loss tangent follows a similar trend to that of the dielectric constant except for an additional low-frequency relaxation peak of about 543 K. The dielectric loss tangent exhibits low value in low temperature and high-frequency regions, indicating that the sample can be a potential candidate for data storage devices. The ferroelectric recording shows a non-linear PE loop at room temperature. The room temperature magnetic recordings show evidence of weak ferromagnetism due to suppression of spiral spin structure as opposed to the antiferromagnetic nature of BiFeO3. The coexistence of these unique features enables the synthesized sample to be used in voltage-controlled data storage devices.

Insight into dislocation activity during ECAP processing of AISI 304 stainless steel studied by X-ray diffraction profile analysis

Insight into dislocation activity during ECAP processing of AISI 304 stainless steel studied by X-ray diffraction profile analysis

Structural Transformations in Cold-Rolled Austenitic Chromium-Nickel Steel Studied by Synchrotron X-Ray Diffraction and Peak Profile Analysis

Structural Transformations in Cold-Rolled Austenitic Chromium-Nickel Steel Studied by Synchrotron X-Ray Diffraction and Peak Profile Analysis